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From: David Howells <dhowells@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: dhowells@redhat.com,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	"hugh.dickins" <hugh.dickins@tiscali.co.uk>,
	lkml <linux-kernel@vger.kernel.org>,
	linux-arch <linux-arch@vger.kernel.org>
Subject: Re: [RFC][PATCH] kmap_atomic_push
Date: Thu, 08 Oct 2009 23:58:30 +0100	[thread overview]
Message-ID: <13794.1255042710@redhat.com> (raw)
In-Reply-To: <1255040942.17055.21.camel@laptop>

Peter Zijlstra <peterz@infradead.org> wrote:

> I can think of code that does a lot more than that, suppose you have
> both KM_USER[01], get an interrupt that takes KM_IRQ[01], take an NMI
> that takes KM_NMI.

But whilst the interrupt might want to use two slots, it's probably a bug for
it to want to access the mappings set up by whatever called KM_USER[01] - so
it can probably reuse those slots, provided it puts them back again.

Similarly for NMI taking KM_NMI - it probably shouldn't be attempting to
access the mappings set up by the normal mode or the interrupt mode - in which
case, why can't it reuse those slots?

> Maybe we can stack the SOFTIRQ ones in as well ;-)

Ditto.

David

  reply	other threads:[~2009-10-08 23:00 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-08 15:35 [RFC][PATCH] kmap_atomic_push Peter Zijlstra
2009-10-08 15:44 ` Linus Torvalds
2009-10-08 15:53 ` Ingo Molnar
2009-10-08 16:29   ` Peter Zijlstra
2009-10-08 16:50     ` Linus Torvalds
2009-10-08 18:02       ` Hugh Dickins
2009-10-08 22:27         ` jim owens
2009-10-08 22:32           ` Peter Zijlstra
2009-10-08 22:57           ` Peter Zijlstra
2009-10-09 12:15             ` jim owens
2009-10-08 22:12 ` David Howells
2009-10-08 22:29   ` Peter Zijlstra
2009-10-08 22:58     ` David Howells [this message]
2009-10-08 22:42 ` Peter Zijlstra
2009-10-08 22:42   ` Peter Zijlstra
2009-10-12 18:10 ` Andi Kleen
2009-10-12 18:30   ` Linus Torvalds
2009-10-12 18:40     ` Andi Kleen

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